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Thread: ESE's works engine tuner

  1. #24181
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    3rd December 2011 - 23:33
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    Quote Originally Posted by jonny quest View Post
    Tell me what you used for inertia wheel on your dyno
    Assume this was for me?

    The wheel was from another dyno... I believe a guy made a few of these quite some time ago. It really is a little too small but it is better than nothing. If we increase the gearing of our bikes it will increase the length of the runs while not exceeding the burst speed of the roller (according to my calculations!?)

    Idealy I would want to upgrade to this at some point: http://www.dynomet.dk/en_diydynoparts.htm

    The dyno chassis can easily be modified to accept the dynomet roller.

    Dave

  2. #24182
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    27th October 2013 - 08:53
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    Quote Originally Posted by lodgernz View Post
    You probably can match the squish to the piston dome.
    It sounds like you have a lathe, and it probably has a swiveling toolpost, locked in place by grubscrews or a handle. Once you identify the exact radius of the piston dome, you can set the tip of the tool to be slightly less than that radius from the centre of the toolpost swivel. I say slightly less, because you want to avoid a negative squish angle (=deto), so the squish band radius needs to be a little tighter to produce a positive (diverging) or neutral squish angle.
    Then with the grubscrews or handle loosened, you just swivel the toolpost assembly back and forth by hand, taking tiny cuts (since it won't be mechanically controlled). Works a treat.

    Hardest part is identifying the exact centre of the toolpost pivot. Piston dome radius can also be tough to determine as some aren't a pure spherical cap.

    Obviously this technique won't be feasible if the dome radius is more than about 100mm.
    the problem is the local machinist does mostly automotive stuff and says he cant do a radius in the head band. either he doesn't know how or his machine isn't capable. so for now I wont have a radius in the head band until I can send the head off to someone else. heres what I have since the last bit of cutting.

    1- band width 16mm , bore 91mm = 58% of total area. to get this closer to 50% I need to be about 13mm wide.

    2- piston gap at bore edge is 1.34mm- 1.58mm going toward center at 16mm. if I cut the band width to 13mm ill have 1.34mm-1.48mm because the flat head band and radius piston

    3- piston at tdc I was only able to fill with 27cc oil which gives 20.5 comp ratio , 528+27/27. far to high im thinking. increasing it to 34cc would give 16.5 and this is likely better maybe. even for methanol. then again I haven't a clue what im doing

    4- the plug is now much closer to the piston top but I will have to check that tomorrow. didn't wob say this is not important ?

    5- local guy says he should be able to cut into the bowl if its a true hemi shape but anything like a bathtub style is totally out of the question

    6 - so is there any easy way to figure how much volume ill gain by cutting the band 3mm narrower. so I end up with 13mm wide (50% approx) and 7cc more than I have now ? this is getting a real pain in the neck

    oh one more question. originally the head used bolts going into the cylinder. ive since installed studs and will clamp it with nuts. do you reckon the torque value should still be about the same or close ?
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  3. #24183
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    24th July 2006 - 11:53
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    Quote Originally Posted by peewee View Post
    originally the head used bolts going into the cylinder. ive since installed studs and will clamp it with nuts. do you reckon the torque value should still be about the same or close ?
    Bit less torque required on the nuts to get the same clamping force, there's just less friction from surface area with studs/nuts than there was with bolts. Can't help with exactly how much less though.

    The best measure of the clamping force is bolt/stud elongation, and it's not unusual on critical applications to torque fasteners to a set elongation. However, unless you can get a micrometer over the full length of the fastener that's difficult to do, you can use a DTI on studs but as you're supposed to torque each stud incrementally in turn you'd have to set up a parallel bar over a reference face to measure from.
    Go soothingly on the grease mud, as there lurks the skid demon

  4. #24184
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    27th October 2013 - 08:53
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    original bolt torq was 25 lbft. 2-3 lbft less should do the trick. good news is it held 20 lbft in a static condition last night with out pulling the studs from the cylinder. I severly over heated the cylinder during welding so im a bit nervous. not to mention I welded for hours on it

  5. #24185
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    20th April 2011 - 08:45
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    Quote Originally Posted by peewee View Post
    piston gap at bore edge is 1.34mm- 1.58mm going toward center at 16mm. if I cut the band width to 13mm ill have 1.34mm-1.48mm because the flat head band and radius piston.
    That's not a squish gap but a deto gap. If you reduce it to half of what it is now, it will raise the compression even further but it will nevertheless reduce the deto risk.

    the plug is now much closer to the piston top but I will have to check that tomorrow. didn't wob say this is not important ?
    He did, and so do I.

    local guy says he should be able to cut into the bowl if its a true hemi shape but anything like a bathtub style is totally out of the question.
    If he can cut a hemi shape, he can also cut an off-center hemi shape which is what you need, or you'll never approach the required volume.

    originally the head used bolts going into the cylinder. ive since installed studs and will clamp it with nuts. do you reckon the torque value should still be about the same or close ?
    I'm not so much worried about the studs, but what about the strength of the head itself? If you remove the required volume, will it still be strong enough for that methanol-compression?

    is there any easy way to figure how much volume ill gain by cutting the band 3mm narrower. so I end up with 13mm wide (50% approx) and 7cc more than I have now ?
    use this: HEAD.zip

    It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape.
    I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card.
    I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
    And in case you are using Windows 10: may God have mercy on you.

  6. #24186
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    23rd September 2014 - 19:35
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    I've reshaped/resized combustion chambers and cut new squishbands with an electric hand drill clamped in the vice, a dremel, files, and sandpaper glued to a piston.
    Not the most precise method, but it works ok.
    Great idea for a poor mans how to video I think!
    Check out my YouTube channel! - 2STROKE STUFFING -
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    Two strokes & rum!

  7. #24187
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    Quote Originally Posted by adegnes View Post
    I've reshaped/resized combustion chambers and cut new squishbands with an electric hand drill clamped in the vice, a dremel, files, and sandpaper glued to a piston.
    Not the most precise method, but it works ok.
    Great idea for a poor mans how to video I think!
    Yes id love to see that... cause im really poor

  8. #24188
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    25th March 2004 - 17:22
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    Well an extraction fan fell into my hands last night. Its only a pitiful 150mm unit but its got to be better than nothing i can'tsee it being a rrestriction. Now Ijust need to score some flexible ducting and think of a decent way to hold it near the exhaust without it getting snagged by the rear wheel spinning on the dyno roller.
    I've been told. Dreaming`s free.
    Think I'll go, back to sleep.
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    Everybody listen, do yours say, what mine says?

  9. #24189
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    Quote Originally Posted by F5 Dave View Post
    Well an extraction fan fell into my hands last night. Its only a pitiful 150mm unit but its got to be better than nothing i can'tsee it being a rrestriction. Now Ijust need to score some flexible ducting and think of a decent way to hold it near the exhaust without it getting snagged by the rear wheel spinning on the dyno roller.
    I've got ya covered for ducting.

  10. #24190
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    2nd March 2013 - 15:04
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    Quote Originally Posted by Frits Overmars View Post
    use this: HEAD.zip

    It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape.
    I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card.
    I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
    And in case you are using Windows 10: may God have mercy on you.
    Seems to run on Win/2000 too, but returns an error message "no cylinder head files found. press Enter to continue".
    Pressing Enter then exits the program.
    Something missing?

  11. #24191
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    egt sensor placement

    What is the correct distance down the pipe from the piston to install a egt sensor? I've heard 200mm.

  12. #24192
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    Quote Originally Posted by Frits Overmars View Post
    That's not a squish gap but a deto gap. If you reduce it to half of what it is now, it will raise the compression even further but it will nevertheless reduce the deto risk.

    He did, and so do I.

    If he can cut a hemi shape, he can also cut an off-center hemi shape which is what you need, or you'll never approach the required volume.

    I'm not so much worried about the studs, but what about the strength of the head itself? If you remove the required volume, will it still be strong enough for that methanol-compression?

    use this: HEAD.zip

    It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape.
    I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card.
    I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
    And in case you are using Windows 10: may God have mercy on you.
    thnx for the help frits. I have win7 so ill give it a try. I was worried about how thick the chamber was since I cut quit far into it. originally I was going to drill a hole and measure thickness then weld the hole shut but I forgot. whats the worst that could happen now, chamber cracks and I lose some water into the cylinder and it smokes more than normal . im sure the methanol would be happy at 20/1 but the engine probly wouldn't and wouldn't that high comp ratio put a damper on the rpm limit and cause who knows how many other problems ? the local machinist doesn't have a cnc that I know of but I have some other people out of town I can send it off to. first ill talk to the local guy and see if theres any way he can do it

  13. #24193
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    13th October 2016 - 17:41
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    Can you measure how much 'meat' is left in the chamber?

    P-W, try flicking an email to this bloke: http://www.twostrokeperformance.com....ish-clearance/

    Dave does re-profile quite a few KTM 2T heads, & has done some monster 2T cylinder dirt bikes too..
    & as a helpful enthusiast, he'll likely give you some pointers of value..

  14. #24194
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    nice idea but with my luck it would get lost in customs and I have to start over with a part that's already rare as hens teeth. try finding a ktm500 head before july

  15. #24195
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    Quote Originally Posted by Frits Overmars
    use this: HEAD.zip. It will allow you to combine any conceivable piston shape with any conceivable combustion chamber shape and display all relevant CNC coordinates, so any machinist worthy of that title will know how to produce your desired head shape. I wrote this program a long time ago; it runs on Windows-versions from DOS 6 to Win98 and on some XP-machines, depending on their graphics card. I myself run it on Win7 with a Win98-emulator, but I just found a simpler solution for you: if you restart Win7 in Safe Mode, it will also run, although not with all its original sparkling colours.
    Quote Originally Posted by lodgernz View Post
    Seems to run on Win/2000 too, but returns an error message "no cylinder head files found. press Enter to continue". Pressing Enter then exits the program. Something missing?
    Yep. I forgot to add a HEAD data sample. I could send one, but first I'll try to write an improved version of the HEAD-program that will deal with this data-less situation. I'll be back.

    EDIT: this should do it: HEAD.zip

    Please let me know if there are any more problems. That HEAD-program should behave now. It was not initially meant to stand-alone; it was part of a bunch of programs that I am planning to make available to you guys, but that will still take some testing.

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